01040nas a2200157   4500008004100000022001400041245008700055210006900142260011000211300001400321490000700335520038500342100002000727700002200747856011300769       2012                        eng d  a1359-734500aEncapsulation of enzyme in large mesoporous material with small mesoporous windows0 aEncapsulation of enzyme in large mesoporous material with small   aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcJUN  a7853-78550 v483 a<p>Trypsin has been encapsulated in the mesopores of a hierarchical mesoporous silica material synthesized via Cu(I) catalyzed azide-alkyne click reaction between azide functionalized large spherical SBA-15 particles and alkyne functionalized mesoporous silica nanoparticles (MSNs). Encapsulated trypsin functions as an efficient biocatalyst and can be recycled several times.</p>1 aMalvi, Bharmana1 aGupta, Sayam, Sen  uhttps://library.ncl.res.in/content/encapsulation-enzyme-large-mesoporous-material-small-mesoporous-windows-001056nas a2200181   4500008004100000245011300041210006900154260000800223300001600231490000700247520038800254100001800642700002400660700002200684700001800706700002200724856012800746       2016                        eng d00aElectrocatalytic water oxidation by a molecular cobalt complex through a high valent cobalt oxo intermediate0 aElectrocatalytic water oxidation by a molecular cobalt complex t  cAUG  a11787-117900 v523 aBiuret-modified tetraamidomacrocyclic cobalt complex [Co-III-bTAML]- is shown to catalyze electrochemical water oxidation at basic pH leading to the formation of O-2. Electrochemical and spectroscopic studies indicate a high valent cobalt oxo intermediate isoelectronic to Co-V(O) as the active oxidant. The kinetic isotope effect of 8.63 indicates an atom proton transfer mechanism.1 aDas, Debasree1 aPattanayak, Santanu1 aSingh, Kundan, K.1 aGarai, Bikash1 aGupta, Sayam, Sen  uhttps://library.ncl.res.in/content/electrocatalytic-water-oxidation-molecular-cobalt-complex-through-high-valent-cobalt-oxo02275nas a2200205   4500008004100000245010900041210006900150260000800219300001400227490000800241520153900249100002401788700002901812700001801841700002201859700001501881700002001896700002201916856013101938       2017                        eng d00aElectrochemical formation of Fe-V (O) and mechanism of its reaction with water during O-O bond formation0 aElectrochemical formation of FeV O and mechanism of its reaction  cMAR  a3414-34240 v23 3 aA detailed electrochemical investigation of a series of iron complexes (biuret-modified tetraamido iron macrocycles FeIII-bTAML), including the first electrochemical generation of Fe-V(O), and demonstration of their efficacy as homogeneous catalysts for electrochemical water oxidation (WO) in aqueous medium are reported. Spectroelectrochemical and mass spectral studies indicated FeV(O) as the active oxidant, formed due to two redox transitions, which were assigned as Fe-IV(O)/Fe-III(OH2)and Fe-V(O)/Fe-IV(O). The spectral properties of both of these high-valent iron oxo species perfectly match those of their chemically synthesised versions, which were thoroughly characterised by several spectroscopic techniques. The O-O bond-formation step occurs by nucleophilic attack of H2O on FeV(O). A kinetic isotope effect of 3.2 indicates an atom-proton transfer (APT) mechanism. The reaction of chemically synthesised Fe-V(O) in CH3CN and water was directly probed by electrochemistry and was found to be first-order in water. The pK(a) value of the buffer base plays a critical role in the rate-determining step by increasing the reaction rate several-fold. The electronic effect on redox potential, WO rates, and onset overpotential was studied by employing a series of iron complexes. The catalytic activity was enhanced by the presence of electron-withdrawing groups on the bTAML framework. Changing the substituents from OMe to NO2 resulted in an eightfold increase in reaction rate, while the overpotential increased threefold.1 aPattanayak, Santanu1 aChowdhury, Debarati, Roy1 aGarai, Bikash1 aSingh, Kundan, K.1 aPaul, Amit1 aDhar, Basab, B.1 aGupta, Sayam, Sen  uhttps://library.ncl.res.in/content/electrochemical-formation-fe-v-o-and-mechanism-its-reaction-water-during-o-o-bond-formation01993nas a2200205   4500008004100000022001400041245006700055210006700122260000800189300001000197490000800207520135400215100002101569700001801590700001801608700002301626700001901649700002201668856009701690       2022                        eng d  a1359-664000aElectrocatalytic alcohol oxidation by a molecular iron complex0 aElectrocatalytic alcohol oxidation by a molecular iron complex  cMAY  a42-570 v2343 a<p>
	An efficient electrochemical method for the selective oxidation of alcohols to their corresponding aldehydes/ketones using a biomimetic iron complex, [(bTAML)Fe-III-OH2](-), as the redox mediator in an undivided electrochemical cell with inexpensive carbon and nickel electrodes using water as an oxygen source is reported. The substrate scope also includes alcohols that contain O and N heteroatoms in the scaffold, which are well tolerated under these reaction conditions. Mechanistic studies show the involvement of a high-valent Fe-V(O) species, [(bTAML)Fe-V(O)](-), formed via PCET (overall 2H(+)/2e(-)) from [(bTAML)Fe-III-OH2](-) at 0.77 V (vs. Fc(+)/Fc). Moreover, electrokinetic studies of the oxidation of C-H bonds indicate a second-order reaction, with the C-H abstraction by Fe-V(O) being the rate-determining step. The overall mechanism, studied using linear free energy relationships and radical clocks, indicates a ``net hydride'' transfer, leading to the oxidation of the alcohol to the corresponding aldehyde or ketone. When the reaction was carried out at pH &gt; 11, the reaction could be carried out at a similar to 500 mV lower potential than that at pH 8, albeit with reduced reaction rates. The reactive intermediate involved at pH &gt; 11 is the corresponding one-electron oxidized [(bTAML)Fe-IV(O)](2-) species.</p>
1 aKuiry, Himangshu1 aDas, Debasree1 aDas, Soumadip1 aChakraborty, Soham1 aChandra, Bittu1 aGupta, Sayam, Sen  uhttps://library.ncl.res.in/content/electrocatalytic-alcohol-oxidation-molecular-iron-complex